This invention relates in general to electrophotographic reproduction machines, and more specifically to a slide transparency projector apparatus for use with an electrophotographic reproduction machine.
In typical electrophotographic reproduction machines (copiers or copier/duplicators), information to be reproduced is reduced to a latent image charge pattern on a photoconductive member. The charge pattern is developed with pigmented marking particles, and the developed charge pattern is subsequently transferred and fixed to a final receiver member to form the desired reproduction. The information to be reproduced is generally in the form of an original (hard copy) document or electronically stored data. When utilizing original documents, a document is placed on a transparent platen and illuminated to form a reflected light image of the document. The reflected light image is projected along an optical path to expose the photoconductive member and alter a uniform charge on the photoconductive member to form a latent image charge pattern corresponding image-wise to the reflected light image. When utilizing electronically stored data, electronic signals representative of data serves to drive a writer such as a laser or LED array to expose the photoconductive member and alter a uniform charge on the photoconductive member to form a latent image charge pattern corresponding image-wise to the data.
With the development of electrophotographic reproduction machines capable of reproducing information in multi-colors, it has become desirable to make reproductions wherein multi-color transparencies such as 35 mm slides are utilized as the information source. U.S. Pat. No. 4,027,962, issued Jun. 7, 1977, in the name of Mailoux, shows an exemplary projector apparatus for enabling a multi-color electrophotographic reproduction machine to reproduce transparencies or slides. Such apparatus includes a projector associated with the reproduction machine and a Fresnel lens, dot screen, and composition frame positioned on the transparent platen of the reproduction machine. The projector directs an image of the transparency through the Fresnel lens, dot screen, and composition frame onto the platen. The location of the Fresnel lens on the platen results in the facets of the lens, and any scratches or imperfections, showing up as undesirable artifacts in the transparency reproduction.